THE SKULL THE CRANIUM 



167 



inner third of its almost horizontal lower margin, where it springs 

 from the side of the basilar process, is rounded and faintly emarginate. 

 This emargination is known as the jugular notch, and forms the back 

 margin of the jugular foramen. In its outer two-thirds the margin 

 is more or less convex, prominent and tubercular, and is directed 

 outward and slightly upward. It overlaps the auditory bulla and 

 affords attachment to the stylohyoid and digastric muscles. On the 

 posterior surface of the process is inserted the obliquus lateralis 



Fm. 111. 



Supraoccipital. 



With Interparietal. 



Fossxfor Cerebellar Lobes. 4 



With Parietal. 



Posterior Condyloid Foramen. 

 Groove for Lateral Sinus. 



Fossa for Auditory Bulla. 



Jugular Notch 



With Temporal. 



y Exoccipital. 

 Anterior Condyloid Foramen. 



Basioccipital, 

 with Basisphenoid. 



OCCIPITAL BONE, INNER OR ANTERIOR SURFACE. 



muscle. The anterior or internal surface (Fig. Ill) of the jugular 

 process is triangular, with the apex of the triangle above. 



At the inner side of its lower margin, in the jugular notch, is the 

 anterior opening of the anterior condyloid canal, above which a 

 faint groove ascends upward and inward. Outside of these markings 

 is a moderately wide, shallow, vertical groove, which passes from below 

 upward and outward and is the lower end of the groove for the lateral 

 sinus ending in the jugular foramen. Outside of this again, and 

 occupying most of the surface, is a rough triangular fossa, which faces 

 downward and forward, and into which is fitted the posterior end of the 

 auditory bulla. Above this fossa is a smaller, less rough, triangular 

 area, which joins the posterior end of the petrous part of the temporal 

 bone. These triangular spaces are limited on the outside by the rough 

 border for articulation witli the mastoid part of the temporal bone. 



